Thorax - Bony Structures PDF

The Thorax – bony structures Anna Rees Context Intended Learning Outcomes Loading… What is the thorax? Thoracic skeleton Loading… Intercostal space Contents of the thorax  Overview of bones Sternum Ribs Costal cartilages Thoracic verteb...

The Thorax – bony structures Anna Rees Context Intended Learning Outcomes Loading… What is the thorax? Thoracic skeleton Loading… Intercostal space Contents of the thorax  Overview of bones Sternum Ribs Costal cartilages Thoracic vertebrae (focus on articular facets articulating with ribs) Sternum Ribcage (including costal cartilage) Typical rib Loading… How does a rib articulate with the thoracic vertebrae? Joints of the thoracic cage For each of the below joints you need to know What type of joint is it? Which bones articulate? State the ligaments What movements occur at the joint Intervertebral, Costovertebral, Costochondral, Interchondral, Sternochondral, Sternoclavicular, Manubriosternal, Xiphisternal Intervertebral (of vertebrae T1-T12), Costovertebral Costochondral Interchondral joint Sternal joints Summary – thoracic cage (bones and joints) a skeletal framework, fascia, muscles, and neurovasculature – all connected together to form a strong and protective yet flexible cage. two major openings: the superior thoracic aperture found superiorly and the inferior thoracic aperture located inferiorly. superior thoracic aperture opens towards the neck. It is bounded by the bones of the upper thorax; manubrium of sternum, the first pair of ribs, and the body of the vertebra T1. inferior thoracic aperture is almost completely covered by the diaphragm, separating it from the abdominal cavity. thoracic skeleton is made up of the sternum, twelve pairs of ribs, twelve thoracic vertebrae, and interconnecting joints. main thoracic joints include the intervertebral discs, costovertebral, sternocostal, sternoclavicular, costochondral, and interchondral joints. running between every two adjacent ribs are anatomical spaces called intercostal spaces (11) ,each one containing the intercostal muscles (external, internal, and innermost) together with the intercostal neurovascular bundle. Summary – Main contents of thorax Heart Lungs Oesophagus Trachea main bronchi Thymus Vagus and phrenic nerves Sympathetic trunks and ganglia Thoracic duct Lymph nodes Major systemic and pulmonary vasculature  Summary - Sternum flat, narrow bone located in the centre of the anterior thoracic wall consists of three parts o superior part is the manubrium o the middle and largest part is the body o and the inferior, smallest part is the xiphoid process junction of the manubrium and body forms the sternal angle The manubrium has a depression on its superior surface, the suprasternal/jugular notch.  Summary - Ribcage First through seventh pairs of ribs have a direct anterior attachment to the sternum by a strip of hyaline cartilage called costal cartilage. Costal cartilages contribute to the elasticity of the thoracic cage and prevent various blows to the chest from fracturing the sternum and/or ribs. Ribs that have costal cartilages and attach directly to the sternum are called true ribs. The articulations formed between the true ribs and the sternum are called sternocostal joints. Remaining five pairs of ribs are termed false ribs because their costal cartilages either attach indirectly to the sternum or do not attach to the sternum at all. The cartilages of the eighth, ninth, and tenth pairs of ribs attach to one another and then to the cartilages of the seventh pair of ribs. These false ribs are called vertebrochondral ribs. The eleventh and twelfth pairs of ribs are false ribs designated as floating (vertebral) ribs because the costal cartilages at their anterior ends do not attach to the sternum at all. These ribs attach only posteriorly to the thoracic vertebrae.  Summary – typical rib Head is a projection at the posterior end of the rib that contains a pair of articular facets (superior and inferior). The facet of the head may fit either into a facet on the body of a single vertebra or into the demifacets of two adjoining vertebrae to form a vertebrocostal joint. The neck is a constricted portion of a rib just lateral to the head and necks are different lengths. A knoblike structure on the posterior surface, where the neck joins the body, is called a tubercle The nonarticular part of the tubercle attaches to the transverse process of a vertebra by a ligament (lateral costotransverse ligament). The articular part of the tubercle articulates with the facet of a transverse process of a vertebra to form vertebrocostal joints. The body (shaft) is the main part of the rib. A short distance beyond the tubercle, an abrupt change in the curvature of the shaft occurs. This point is called the costal angle. The inner surface of the rib has a costal groove that protects the intercostal blood vessels and a small nerve.  Summary – Articulation with thoracic vertebra The posterior portion of the rib connects to a thoracic vertebra by its head and the articular part of a tubercle. The facet of the head fits into either a facet on the body of one vertebra (T1 only) or into the demifacets of two adjoining vertebrae. The articular part of the tubercle articulates with the facet of the transverse process of the vertebra  Summary – joints of thoracic cage